We proposed that there is increased expression of neutrophil and endothelial adhesion molecules CR3, L-selectin, soluble E-selectin, soluble L-selectin and soluble ICAM-1 in bronchopulmonary dysplasia (BPD), which may be early markers of this condition. Furthermore, we postulated that therapeutic use of steroid will inhibit production of these adhesion molecules and may also downregulate lymphocytic function. We also hypothesized that neutrophil burst activity of circulating neutrophils is increased in BPD and this may explain the lung injury in these infants.